Well, I own both (actually, two 710's, and one Military). And, I'm actually carrying both right now. There has been MUCH said about both of these, but here is what stands out to me.
Both of the knives are about the same length closed. Well, nearly. The Military is about a half inch longer. The 710 is thicker (side to side), but the Military is wider (spine to edge). The makes a big difference when it comes down to carrying them. I have no problem comfortably carrying the Military IWB, clipped behind my belt. This makes for an extremely covert carry, in spite of the fact that there is at least 3/4" of the handle sticking up above the waist band. My shirt just falls naturally over it and it is hidden. To comfortably carry the 710, I need to clip it to a pocket. I can carry it IWB as well, very well concealed, but over long term it starts to become unfortable because of its shape and thickness.
The steels of the blades are just not that much different, IMO. Both the ATS-34 and the 440V take a nice edge, and hold it just as well. Or so close that I can't discern a difference. The 440V takes a slightly keener edge, so it feels sharper. But, in actually using the two, there just isn't much difference. If you're going to use the knife a lot for utility, I would probably upgrade to the 710HS (with M2 steel), as that is by far my favorite steel. It takes a keener edge than either ATS-34 or 440V, and holds it just as long or longer than either. It just isn't stainless, but that isn't a factor for me.
I carry the Military as my using/utility knife. I carry the 710 for any use where I absolutely, positively have to trust the lock. The 710 is my substitute for the fixed blades that are a little difficult to carry covertly in the summer. The Military has a strong lock, but it is a liner lock, and I just won't trust that lock as much as the axis lock, ultimately.
So, I hope all this rambling helps a bit, or at least gives you some things to think about. If you have more questions, you can post them here, or e-mail me directly. And I'm sure as soon as some others see this thread, you'll get plenty more answers.
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iktomi